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The role of viscous magma mush spreading in volcanic flank motion at Kīlauea Volcano, Hawai‘i
- Source :
- Journal of Geophysical Research: Solid Earth. 118:2474-2487
- Publication Year :
- 2013
- Publisher :
- American Geophysical Union (AGU), 2013.
-
Abstract
- [1] Multiple mechanisms have been suggested to explain seaward motion of the south flank of Kīlauea Volcano, Hawai‘i. The consistency of flank motion during both waxing and waning magmatic activity at Kīlauea suggests that a continuously acting force, like gravity body force, plays a substantial role. Using finite element models, we test whether gravity is the principal driver of long-term motion of Kīlauea's flank. We compare our model results to geodetic data from Global Positioning System and interferometric synthetic aperture radar during a time period with few magmatic and tectonic events (2000–2003), when deformation of Kīlauea was dominated by summit subsidence and seaward motion of the south flank. We find that gravity-only models can reproduce the horizontal surface velocities if we incorporate a regional decollement fault and a deep, low-viscosity magma mush zone. To obtain quasi steady state horizontal surface velocities that explain the long-term seaward motion of the flank, we find that an additional weak zone is needed, which is an extensional rift zone above the magma mush. The spreading rate in our model is mainly controlled by the magma mush viscosity, while its density plays a less significant role. We find that a viscosity of 2.5 × 1017–2.5 × 1019 Pa s for the magma mush provides an acceptable fit to the observed horizontal surface deformation. Using high magma mush viscosities, such as 2.5 × 1019 Pa s, the deformation rates remain more steady state over longer time scales. These models explain a significant amount of the observed subsidence at Kīlauea's summit. Some of the remaining subsidence is probably a result of magma withdrawal from subsurface reservoirs.
- Subjects :
- geography
Flank
geography.geographical_feature_category
Mush zone
010504 meteorology & atmospheric sciences
Subsidence
Fault (geology)
010502 geochemistry & geophysics
01 natural sciences
Geophysics
Volcano
13. Climate action
Space and Planetary Science
Geochemistry and Petrology
Magma
Interferometric synthetic aperture radar
Earth and Planetary Sciences (miscellaneous)
Rift zone
Geology
Seismology
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 21699313
- Volume :
- 118
- Database :
- OpenAIRE
- Journal :
- Journal of Geophysical Research: Solid Earth
- Accession number :
- edsair.doi...........31eac60caa2d423a79d139f31c49903d
- Full Text :
- https://doi.org/10.1002/jgrb.50194